As you know, various parts of fasteners are present in many products. And most people are faced with this constantly. This is especially true for construction and repair work. So what to use for fixing certain materials or structures? How is a screw different from a self-tapping screw, what is the difference between these fasteners?
It would seem that at first glance these products are no different from each other. For a long time it was believed that the screw is a type of self-tapping screw. But do not make premature conclusions. Before performing repair work, it is better to understand in detail how the screw differs from a self-tapping screw. Photos of these fasteners are presented in the article. At first glance, they are similar, but in fact there are many differences.
What is a self-tapping screw?
This is a fastener with a special thread. It is a rod with a head having an external thread. Self-tapping screws are made of stainless or carbon steel. Made in accordance with GOST 27017-86 "Fasteners. Terms and Definitions". To protect against the corrosion process at the production stage, such products are phosphated, galvanized or oxidized.
What are they for?
Self-tapping screws are designed for fastening various structures or their elements to solid bases. Due to their self-tapping ability, they do not require additional measures, such as drilling holes. The thread on the screws is applied to the entire cylindrical surface of the rod. Thanks to this, more reliable fixation and fastening takes place.
Varieties of screws
Such fasteners can vary in several ways:
- By appointment: for metal, plastic, wood, drywall, etc.
- By type of head: semicircular, cylindrical, countersunk, press washer (used for roofing), a truncated cone, six-sided (used with a plastic expansion bolt shield to attach heavy objects).
- By type of tip. The tip of the screw can be sharp or made in the form of a drill. Such products are used for fastening metal.
- By type of slot. Simply put, under the guise of a screwdriver: straight, cross-shaped, hexagonal (furniture).
- By the type of thread. Frequent - for metal and plastic, rare - for woodwork. There are also self-tapping screws with a thread of a mixed type, most often closer to the head it becomes less common. Such elements are used to fasten structures to concrete substrates and are made of high alloy steels.
It is worth noting that the self-tapping screws for attaching gypsum sheets differ in a special head, it is countersunk and has a thread directly on the head itself.
What is a screw?
A screw, like a self-tapping screw, is a cylindrical rod with different types of head and external thread. Designed for attaching various elements to soft substrates. It has a cap and a cylindrical part, which is partially covered by a thread, which makes it different from a self-tapping screw.
When screwing in a screw, it is necessary to drill a hole with a diameter of up to 70% of the thickness of the screw. This is the main difference, showing how the screw differs from the self-tapping screw. When working with this fastener, it is important to choose the diameter of the drill in order to qualitatively perform the connection of materials. Screws provide a durable and most often non-separable connection of parts.
Where is it used?
A feature of the screw is the fact that it can be used to fasten structures with moving parts. This is possible due to the fact that part of the cylindrical base has no thread.
Varieties of screws
These fasteners are classified in the same way as self-tapping screws:
- Type of hat: semicircular, countersunk, hexagon, square. However, it is worth noting that self-tapping screws have a wider range of caps, so the range of their application is wider.
- In the shape of the tip: blunt (used when screeding furniture or plastic), sharp.
- Rod thread: one-way (large, frequent, small), two-way (the same or variable height).
- Splines. As with self-tapping screws, they can be cruciform, straight, hexagonal.
After the above description of both products, you can combine the obtained data and conduct a comparative analysis, which will show how the screw differs from the self-tapping screw. This will help determine which item is more suitable in a particular case.
How is a screw different from a self-tapping screw: differences
Externally, these fasteners can be very similar, but they have a lot of signs of difference:
- A screw is not such a durable product as a self-tapping screw, which is made of more resistant alloys and is used to fasten a large number of materials. These include metal or concrete products. Therefore, the range of application of screws is wider, in contrast to screws. At the same time, hard alloys are not always convenient for some work. For example, many masters noticed that when working with dense materials, sometimes the heads of self-tapping screws are simply cut off. This causes some inconvenience during operation. While a screw made of soft material does not break, it simply bends. It is easier to replace with a new one.
- There is also a significant difference in the manufacturing technology of these fasteners. All screws undergo heat treatment and are coated with special compounds.
- Another main difference, showing how the screw differs from the self-tapping screw, is that it can not be screwed in without first drilling the hole. This should be taken into account during installation work.
- If you look closely, you can clearly see how the screw differs from a self-tapping screw. This is the height of the thread and its pitch. In addition, with a self-tapping screw, the thread covers its cylindrical part completely.
- Another external difference at the tips. With a self-tapping screw, it is always sharper. However, in rare cases, there are also screws of this kind.
Conclusion
After conducting a comparative analysis, it became clear how the screw differs from a self-tapping screw. Now we can conclude that these are fasteners that are designed to perform different tasks, although they are, in fact, the same. When performing any fixing work, you must first figure out which elements are more appropriate to use.